Garbine Muguruza lost in the second round of the Qatar Total Open. (AP)

Garbine Muguruza, who lost to veteran Shuai Zhang in Qatar, said that she was affected by last weekend’s Fed Cup tie.

Spain lost to the Czech Republic in an away tie, with the 23-year-old losing badly, 6-2, 6-2, to Karolina Pliskova.

“It’s also very difficult for me because we had a very tough opponent,” Muguruza said. “We played Czech Republic, which was [a] very bad draw ... My matches were very hard. You're playing, and you're thinking, 'I have to give it [my] all, I have to play for my team.' You're so motivated. Then you're thinking, 'Tomorrow I have to rush to another place. They're waiting for me.'

"You have this on your mind: 'Man, I don't know how I'm going to do it.'”

The Spaniard’s loss came in her second match of the day in rain-delayed Doha. She defeated Cagla Buyukakcay in the first round.

After winning Roland Garros last year, Muguruza has not won another tournament. She lost early at Wimbledon, at the Olympics, at the U.S. Open and at the WTA Finals. This year, she retired in Brisbane in the semis and was upset by American CoCo Vandeweghe in the quarters of the Australian Open.

But, despite her struggles, being a Grand Slam champion keeps her feeling positive.

“It makes you a little bit more—'responsible' might be the word, not 'pressure,’” Muguruza said. “You have the responsibility of being Grand Slam champion, to always be in the last rounds, I guess. At the end, I always take the good part of that. I have the trophy. I have the self-confidence that gave me.”